Digital fingerprint-scanners are supposed to enable safe identification and verification of people based on biometric data. However, in the past years it has been found that currently used technology is not safe from spoofing attacks. Consequently new technology is being developed. //By Daniel Skowranek

8.11.2017// Biometric checks by a fingerprint-scanner are becoming increasingly more important for modern security measures. Alongside the biometric access control for smartphones, tablets and payment systems, such as PayPal, the importance of access control for high security buildings and rooms is also increasing. Furthermore, as of this past November, German passports are equipped with two additional fingerprints that are saved onto their embedded microprocessor chip.

Current technology is vulnerable to spoofing attacks

Paralleling the rising importance of this technology, criminals are increasingly focused on exploiting their weaknesses. Scientists and hackers have proven that fingerprint scanners are not safe when targeted with the right method, usually involving the application of a well tailored artefact. For example, in January the Japanese National Institute of Informatics scientist Isao Echizen managed to completely reconstruct the fingerprints found on a high-resolution photo that was taken from a range of three meters.

Fingerprint scanners can be tricked in multiple ways

According to the German Federal Office for Information Security (BSI) currently used fingerprint scanning technology is proven to be vulnerable to skin transplants, stickers with an imprint of another person’s fingerprint and the surgical removal of the visible skin ridges. Taking this into consideration, new approaches are required for authenticating one’s identity in a safer and more reliable manner.

OCT-Scanner as a solution

A method that promises just that is based on a well-established medical imaging technique that is referred to as optical coherence tomography (OCT). In contrast to currently used scanning systems, OCT is not only able to create a digital representation of the fingerprints visible ridges and valleys, but also delivers additional biometric information from beneath the topmost skin layer. Thus, OCT has the ability to picture internal structures such as sweat-pores, allowing for the indication of attack-revealing mismatches between the outer skin layers Epidermis and Dermis. The resulting „internal fingerprint“ works as a source template for the outer fingerprint. In addition to this, OCT-Scanners could possibly be used to measure blood flow by taking a sequence of images, enabling the detection of counterfeits and dead tissue.

Project 3D-Finger

Project 3D-Finger is a scientific project headed by the Institute of Safety and Security Research at the University of Applied Sciences Bonn-Rhein-Sieg in Germany. Its primary goal is the creation of a virtually unspoofable fingerprint-scanner utilizing the additional biometric data that OCT-Scanners can provide. The project is lead by Prof. Norbert Jung: “It is not a matter of catching criminals, but of enabling authorities or individuals with corresponding needs to ensure secure authentication, for example in restricted areas.” The reason for this rather exclusive target group is that OCT-Scanning-Technology is still very expensive and creates vast amounts of data. A full-area scan of a fingerprint can create up to eight gigabytes of raw data, making not only the process of scanning, which by itself can last up to several seconds, but also subsequent signal processing a slow procedure. Consequently this technology will likely not be available to the general public in the near future.

OCT-Scanners could be used in Kiosk-Systems...

Being too expensive and slow for general use, OCT-Scanning technology is limited when it comes to it’s application possibilities. According to the Institute of Safety and Security Research employee Alexander Kirfel, OCT-Scanning will likely be used within so called Kiosk-Systems — fully automated systems — that enable users to enroll and authenticate themself in the absence of a human supervisor. For example, these systems could be used at airport terminals.

... or to help prevent infant abduction

Another possible application is the prevention of infant abduction within hospitals. With current technology, it is not possible to retrieve good quality fingerprints from infants, since their skin structure is not developed enough. Thus, there is no secure biometric way of tracking them. OCT-Scanning could solve this by delivering the additional biometric information of the deeper and more developed structures.

Link: Another technikjorunal-article about automatic face recognition (german language).

The author

Daniel Skowranek